In recent years, for example, with a growing use of image-capturing devices such as digital cameras and a development of image processing techniques, there has been an increase in opportunities to display an image of a captured photograph or the like on a display so as to select a target image to be edited or printed, to enjoy the image in a slide-show format, or the like. There is also a case where a plurality of thumbnails of images are printed. In image data, regardless of whether the correct orientation for the composition is vertical or horizontal, pixel values are normally recorded based on the position of an image-receiving element. Thus, an image at the time of display is basically displayed in an orientation that is the same regardless of the composition thereof.
Therefore, it is necessary for a user to individually rotate an image to a correct orientation after the image is displayed or to edit the orientation to the correct orientation on an edit screen so as to set the image as content for a slid show or the like. As one of methods for supporting this task, a technique has been suggested for detecting a skin area of a human figure and then determining the vertical direction of a photograph in accordance with the direction of the alignment of the skin area (see, for example, patent document No. 1).
[Patent Document No. 1] Japanese Patent Application Publication No. 2006-350642